#include <iostream>
// #include <format>

using namespace std;

int main()
{
	char c;
	cin >> c;
	// cout << format("Retrieved {} before putback('e').", c) << endl;
	cout << "Retrieved " << c << " before putback('e')." << endl;

	cin.putback('e'); // 'e' will be the next character read off the stream.
	cin >> c;
	cout << "Retrieved " << c << " after putback('e')." << endl;
}
